[biguc]

Most is easy:

Whistler
Mississauga
Asbestos

Needs no explanation.

Least is more difficult. If something is less Canadian, it implies that Canada would be more Canadian without it. Given that Canada's Canadianess is derived from all of its parts, it can't be more Canadian with less Canadian parts. I'll instead re-frame least Canadian as most not-Canadian and tell you the not-Canadian part.

Winnipeg, Canada's most South African city.
Whistler, Canada's most Australian city.
Niagara Falls, as Canada's worst city, is our most American.